Various types of lubricants may be applied to injection devices that penetrate a patient's tissue. Moreover, needles, such as, for example, needles that are used in the injection or removal of drugs, blood, fluid, or other materials into/from a patient, may be lubricated. Such lubrication may reduce forces associated with the penetration of the needle into/though/from the patient's tissue. For example, by lubricating needles with a needle lubricant, the force needed to open the initial point incision in a patient from the tip of the needle point over the beveled area of the needle point, also referred to as the dilation force, may be minimized. Further, the needle lubricant may also help minimize the force needed to insert the needle to a desired tissue depth in a patient once the needle is inserted past the bevel of the needle point, also referred to as the glide force. Such reductions in dilation and glide forces may allow for a reduction in patient pain that may be associated with the insertion into, and movement of the needle in, the patient's tissue.
Needle lubricants often used to lubricate needles, such as, for example (but not limited to), silicone lubricants that are heat curable, solvent curable, UV curable, or curable in other manners, typically include more than just silicone alone. Such lubricants also typically include carrier solvents and other components, including, for example, volatile organic compounds (VOC), silicone oil, components of the silicone oil, and solvent mix, among solvents and/or components. Yet, such carrier solvents and components may find their way to an interior region of the needle and/or an interior area of a barrel that is in fluid communication with the needle. Further, these contaminants may enter into these interior and inner regions and areas in various phases, such as, for example, as either a liquid, gas or vapor. Yet, when inside the needle or barrel, these solvents and components of the needle lubricant may be deemed undesirable contaminants. For example, such contaminants may negatively impact downstream manufacturing processes, such as the application of coatings to the barrel. The presence of the needle lubricant, or components thereof, may also be contaminants to the drug or other solution(s) that is to be injected into the patient through the barrel and/or needle.
Further, when coating the exterior of the needle with the needle lubricant, such as silicone oil, it is often attempted to provide a confluent, thin, and constant coating thickness of the needle lubricant. However, often attempts to apply such coatings to needles while also preventing needle lubricant from entering into the interior region of the needle results in the formation of bubbles of needle lubricant around the exterior wall of the needle. The movement, sticking, and bursting of such bubbles to/on the exterior wall of the needle results in a rough, non-uniform coating of needle lubricant on the exterior of the needle. Such a non-uniform coating causes higher friction than a uniform coating when the needle is inserted into a patient's tissue, thereby providing non-optimized dilation and glide forces and the risk for an associated increase in patient pain. Additionally, when applying needle lubricant to the needle, there is the potential that a droplet of needle lubricant will form at the tip of the needle. This droplet can also cause an increase in the dilation force, thereby leading to increased patient pain.